Wireless communication networks continue to evolve with enhanced and new features being developed for deployment in current and future generation networks. One particular area of development resides in the area of positioning a mobile station within a wireless network quickly, with high accuracy, and with nominal network traffic. By government mandate, future networks must be able to provide location information with emergency (E-911) calls.
For example, in the United States of America, the Federal Communications Commission (FCC) has mandated that mobile phone handsets provide location information to a Public Safety Answering Point (PSAP) which is the public facility which receives and processes emergency calls. The FCC specifications require positioning to an accuracy of less than 50 meters. This allows emergency personnel or police to be able to locate and help the caller in cases where the caller may not know his/her location, or when he may be unable to speak.
It is often desirable to position mobile phones on demand as well. For example, on demand mobile phone positioning is finding acceptance in commercial applications, such as in fleet management for rental car fleets, and to obtain position on demand to aid in navigation.
Unfortunately, the positioning of a mobile phone is particularly difficult due to a several factors. First, positioning of a mobile phone is encumbered due to multi-path problems as well as the fading of signals, which make simple triangulation measurements unreliable enough for high accuracy calculations. Time of Arrival (TOA) techniques measure the time it takes to receive synchronized signals that are broadcast from various known points, such as Base Stations (BSs). The TOA information is sent back to a network node, such as a Mobile Switching Center (MSC), which uses an algorithm to roughly determine the position of a mobile. Unfortunately, these techniques can only provide the general position of a mobile phone, and will often fail to meet the high resolution requirements mandated by government agencies.
Mobile phones having Global Positioning System (GPS) receivers therein are one viable solution to providing a position of a mobile phone with high accuracy. GPS is based on triangulating, along lines of sight, with at least three of the many GPS satellites that circle the earth that were launched by the US Government beginning in 1978. GPS is a well-known technology and is used in many military and civilian applications. The resolution of GPS meets the requirements of both the FCC-mandated E-911 service, as well as other market-driven demands. Accordingly, the most common method of providing location data is to have mobile phones with GPS receivers therein.
However, in order to be useful, this geographic information must be communicated to the PSAPs, and the PSAP must be able to process it. Efforts are underway to standardize methods and systems to automatically transmit coordinate information to the PSAPs. Amazingly, although there is a FCC mandate that the carriers must provide location information, there is no FCC mandate that the PSAPs be able to receive it. This may be because the hardware equipment and software upgrades needed to be able to receive the location information at the PSAP will likely be expensive, and thus deployment of location technology within PSAPs may be slow.
Since it may be some time before PSAPs can incorporate location equipment, mobile phones with GPS capability may be sold on the consumer's belief that the mobile phone will provide location information for emergency calls, but in many cases the PSAP that receives an emergency call will not be able to process the information. This will likely cause consumer irritation, or possibly lawsuits. Therefore, what is needed is a system and method of transmitting coordinate information for a mobile phone to a PSAP that uses equipment already available at the PASP.